High yield of minipool NAT in India using a sensitive multiplex assay for blood donor screening

Abstract

Background and Objectives: Nucleic acid amplification testing (nucleic acid testing [NAT]) for blood donor screening is increasingly being adopted in India to reduce the risk of transfusion-transmitted diseases. The high sensitivity of NAT enables testing of a large volume of donations in minipool format; reducing the costs of testing compared to individual donation testing. This study was aimed at evaluating the yield of minipool NAT testing for hepatitis B, hepatitis C, and human immunodeficiency virus (HIV) in blood donors from Uttar Pradesh. Methods: Samples from routine blood donors collected between August 16, 2016, and December 31, 2020, that were seronegative for hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV, syphilis, and malaria were further screened by NAT in pools of six donations (MP6) using the cobas TaqScreen MPX Test, version 2.0 (MPX2) on the cobas s 201 System. Members of reactive pools were tested to identify the reactive donation(s). Viral load testing was performed on randomly selected NAT-reactive samples. Results: Of 172,443 seronegative donors, 463 were NAT reactive: 369 HBV, 89 HCV, 2 HIV, and 3 co-infected with HBV and HCV. The overall NAT yield was 0.27%, with individual virus yield rates of 1/464 for HBV, 1/1874 for HCV, and 1/86,222 for HIV. Viral load testing of 19 HBV NAT-yield donations showed low concentrations in 16 samples and undetectable viral load in three; the two HCV NAT-yield donations tested had high viral loads. Conclusion: Screening of blood donations by minipool NAT using the highly sensitive MPX2 assay identified a high yield of serology negative, NAT-positive donations, including HBV reactive donations with low viral concentrations.

Keywords

• blood donor screening
• minipool
• nucleic acid testing yield
• nucleic acid test
• viral load